Large quantities of food subsidies provided by humans to animal communities have the potential to change a variety of animal life traits, including denning behaviour of facultative hibernators like bears. We studied denning behaviour of European brown bears in Slovenia, where intensive supplemental feeding with corn is practiced throughout the year, including winter. We also conducted a meta-analysis to compare our results with other bear populations across Europe, Asia and North America. A consistent relationship between latitude and time spent denning was observed for male and female brown bears across the species’ range, and males on average denned 10.3 days longer than females throughout the latitudinal gradient. However, our study area deviated strongly from regions where supplemental feeding was not practiced. In Slovenia, denning period averaged 82 days for females and 57 days for males, which was 45 and 56% shorter compared to the time predicted for this latitude, respectively. We also observed regular den abandonments (61% of bears abandoned dens, on average 1.9 times per winter). During the winter period bears increased use of supplemental feeding sites for 61% compared to the non-denning period. We conclude that the availability of anthropogenic food is an important driver of denning behaviour in brown bears.
COBISS.SI-ID: 4578982
We investigated the patterns of damage caused by brown bears Ursus arctos and its ecological and socio-economic correlates at a continental scale. We compiled information about compensation schemes across 26 countries in Europe in 2005–2012 and analysed the variation in the number of compensated claims in relation to (i) bear abundance, (ii) forest availability, (iii) human land use, (iv) management practices and (v) indicators of economic wealth. The mean number of compensated claims per bear and year ranged from 0·1 in Estonia to 8·5 in Norway. This variation was not only due to the differences in compensation schemes; damage claims were less numerous in areas with supplementary feeding and with a high proportion of agricultural land. However, observed variation in compensated damage was not related to bear abundance.
COBISS.SI-ID: 4452006
Diversionary feeding uses food to lure animals away from areas where they are unwanted or could cause conflicts with people. Feeding wildlife is widely practiced in Europe to enhance hunting and reduce conflicts, but feeding of bears is discouraged across North America. The efficacy and potential side-effects of bear feeding remain an open question because of a lack of rigorous studies. Here we examine studies from which we attempt to draw inferences about feeding as a conflict-mitigation strategy. Studies included U.S. national parks, where after bear feeding was banned conflicts were reduced; Aspen, where town dumpsters did not divert bears from using other human-related foods; the Tahoe Basin of California, where an emergency feeding effort seemed to reduce conflicts within approximately 1 km of the feeding site; and Slovenia, where a high density of feeders seemed to divert bears from using settlements. Although none of these studies were true experiments with treatments and controls, the range of circumstances yielded insights into when feeding could be effective: when food demands are not readily met by natural foods; when the provisioned food is easily found outside the potential conflict area; when the food is attractive; and when bears do not associate the feeding with people. Diversionary feeding, if used, should be conducted as an adaptive management strategy by professionals so as to learn more about factors influencing its effectiveness.
COBISS.SI-ID: 4848038
Ethanol storage and lipid extraction can alter the isotopic composition of animal tissues, which can bias dietary estimates calculated by stable isotope mixing models. We examined the effects of ethanol storage and lipid extraction on 13C, 15N, and 34S values measured in brown bear (Ursus arctos) muscles and livers. We also used isotopic data from our experiment to understand the effect of ethanol storage and lipid extraction on dietary contributions calculated by SIMMs. We found that ethanol storage and lipid extraction caused small increases in 13C values for both muscles (ethanol storage: +0.4 prom., lipid extraction: +0.4 prom.) and liver (ethanol storage: +0.6 prom., lipid extraction: +0.8 prom.). In contrast, 15N and 34S values did not change when stored in ethanol or when lipids were extracted from tissues. Ethanol storage and lipid extraction had negligible effects on estimated dietary contributions. We show that a relatively high lipid content in the muscles and livers of some large-bodied terrestrial omnivores do not necessarily have an effect on dietary estimates that rely on carbon stable isotopes. Our results suggest that ethanol storage could be a valuable alternative method for preserving animal tissue prior to stable isotope analysis when freezing or drying is impractical.
COBISS.SI-ID: 5301926
Artificial feeding of wildlife is a widely used tool for a range of conservation and management goals. We used automatic video surveillance to monitor the vertebrate species using artificial feeding sites (n?=?20) established primarily for brown bears (Ursus arctos) in Dinaric Mountains. We also studied how type of artificial food (only plant-based food vs. mixed food including carrion) affects the species diversity and assemblage at the feeding sites. In total, we identified 23 vertebrate taxa, including the brown bear, using the feeding sites. Brown bear, European badger, and red fox were the most frequently recorded species. Birds represented a substantial part (46%) of vertebrate community using the feeding sites, including species of a high conservation importance. Species diversity at the feeding sites was highest in spring while species composition varied both seasonally and according to the type of artificial food (with or without carrion). Our study indicates that artificial feeding affects numerous non-target species, which could have several ecological and management-relevant effects, including potentially undesired consequences. Artificial feeding of wildlife should be carefully planned and we provide recommendations on how to mitigate the side effects on non-target species.
COBISS.SI-ID: 5290150